Tumor microwave ablation (MWA) is a minimally invasive local treatment technique that directly destroys tumor tissue using heat generated by high-frequency electromagnetic waves (microwaves). It is widely applied in the treatment of various solid tumors. Below is a systematic introduction to its core aspects:

Mechanism of Action

* Electromagnetic Energy Conversion: Microwave antennas emit electromagnetic waves at frequencies of 915 MHz or 2.45 GHz, causing water molecules and ions within the tissue to vibrate and rub at high speeds, generating temperatures of 60–150°C.

* Thermal Coagulation Effect: The high temperature causes protein denaturation and DNA fragmentation in tumor cells, leading to irreversible coagulative necrosis. It also inactivates surrounding microvessels, reducing the risk of metastasis.

Indications

Applicable Tumor Types:

* Primary liver cancer (especially single nodules ≤5 cm)

* Metastatic liver cancer (such as colorectal cancer liver metastases)

* Lung cancer (peripheral type ≤3 cm, patients who cannot tolerate surgery)

* Kidney cancer (T1 small tumors with nephron-sparing treatment)

* Bone tumors, thyroid nodules, etc.

Applicable Patient Groups:

* Patients who cannot undergo surgery or refuse open surgery

* Elderly patients with poor cardiopulmonary function

* Patients with multiple lesions requiring staged treatments or combined therapies (such as chemotherapy, immunotherapy)

Technical Procedure

Preoperative Planning:

* Imaging assessment (contrast-enhanced CT/MRI to determine tumor location and blood supply)

* Coagulation function and liver/kidney function tests

Intraoperative Procedure:

* Image guidance: Real-time CT or ultrasound positioning to precisely plan the puncture path

* Local anesthesia: Local anesthesia at the skin puncture site; intravenous sedation if necessary

* Antenna placement: Percutaneous insertion of the microwave antenna into the tumor center to cover the lesion and safety margin

* Energy delivery: Set power (40–100W) and duration (5–30 minutes) based on tumor size to create a spherical ablation zone

Postoperative Management:

* Imaging follow-up (contrast-enhanced CT 24–48 hours post-op to confirm ablation range)

* Monitor vital signs and manage pain or low-grade fever reactions

Advantages

* Efficient thermal field: Strong penetration, less influenced by tissue impedance, large ablation volume, fast speed

* Precise and controllable: Multi-antenna cooperation allows treatment of irregular tumors with high conformity

* Minimally invasive and safe: Requires only 2–3 mm puncture holes, bleeding risk <1%, hospital stay 1–3 days

* Repeatability: Can be used multiple times for recurrent or new lesions

* Synergistic potential: Can enhance effects when combined with TACE, targeted therapy, etc.

Limitations and Risks

* Tumor limitations: Lesions >5 cm are more likely to have residual tumors; require staged or combination therapy

* Anatomical limitations: Caution near large vessels (heat sink effect) or hollow organs (risk of perforation)

Possible Complications:

* Minor: Pain (30%), self-limited bleeding (5%), transient fever (20%)

* Severe: Pneumothorax (\~10% during lung ablation), intestinal fistula (<1%), skin burns (3%)

Research Progress

* Technological innovation: Water-cooled antennas reduce carbonization risk and expand ablation range; AI-assisted temperature monitoring improves accuracy

* Clinical exploration: MWA combined with nanoparticles (e.g., gold nanorods) enhances thermal effects; tumor antigen release may stimulate systemic immunity

Summary

Tumor microwave ablation, with its efficient and minimally invasive characteristics, has become an important tool in multidisciplinary cancer treatment. It is especially suitable for early small tumors and palliative treatment in certain advanced cases. As imaging navigation and energy control technologies continue to improve, the precision and range of indications for MWA are expected to expand further.